Conventional screen printed solar cells have their main advantages lying with their simplicity of fabrication and the associated low production costs. However, there are numerous disadvantages. Screen printed contacts typically have a minimum metallisation width of about 150 .mu.m. The consequence is a fairly high degree of shading of the top surface of the solar cell, often in the vicinity of 12%. In addition, the high shading losses require a minimum spacing between fingers usually of at least 3 mm. This results in the silicon surface requiring very heavy doping to give sufficiently good conductivity in the diffused layer so as to reduce the lateral resistance losses to respectable values. The unfortunate consequence of the heavy doping is a poor response of the solar cell to short wavelength light. This is because the high energy photons generate electron-hole pairs near the surface in the heavily doped region which recombine without contributing to the generated current. Another problem area for screen printed contacts is the associated high contact resistance that is established between the metallisation and the silicon surface. Optimisation of infra-red furnace firing conditions or subsequent immersion in hydrofluoric acid can reduce this problem although neither will totally eliminate it. Finally, any solar cell with the diffused layer confined to the top surface will suffer from a poor response to long wavelength light unless it has extremely long bulk minority carrier lifetimes. Solar cells fabricated on polycrystalline substrates are a good example of such solar cells as they typically will possess bulk minority carrier lifetimes of only about 70 .mu.m for a 1 ohm centimeter resistivity.